Plough plane blades - flared, relieved or square?

[jmk89]

Derek Cohen from Perth wrote a review of the Veritas Small Plough Plane which he posted on the Australian Woodworking Forums:www.woodworkforums.ubeaut.com.au/showthread.php?t=60857

As you will see, I mentioned Alf's review which noted a question of binding of the blade perhaps because the blade is square on all sides and not relieved. This has led to a heated discussion on whether the blade in a plough plane should be:

• square (ie its sides touch the side of the groove that it cuts)
  
• relieved (ie, there is a chamfer on the rear edges of the blade, but the front touches the side of the groove) - like the Stanley and Record blades for their plough/plow planes.
  
• trapezoidal (ie there is a bevel all the way up the blade and on the whole of the side, but the front edges touch the groove sides) - imagine a bevel edged chisel.
  
• flared (the section of the blade is rectangular, but the front and rear faces are reduced slightly from the edges)
  

Has anyone done any experiments on whether square or releived cutters are better? Has anyone used trapezoidal or flared cutters? Does anyone care?

[paulchapman]

Hi Jeremy,

Yes, pity that debate became so heated. In my view Jake is absolutely right in what he says about blades (and planes in general) - I've tried it and it works. The difference between Jake and all his critics is that Jake has the results to prove it - in fact he's the only person I know who actually uses these planes to any significant degree. Pity he receives so much stick from some quarters when he shares his information so freely and for no personal gain....

Cheers

Paul

[Alf]

Hi Jeremy,

Erm, "short-changed" is a little strong interpretation, perhaps?

It's interesting that the plough seems to have brought just about the worst my-way-is-right-therefore-yours-is-wrong reaction. Frankly life's too short to argue when opinion on what's good or bad all comes down to personal experience anyway (in the "this is what I found" meaning, not the boring "I've been doing this longer than you have" one) and there are as many personal experiences are there are persons. We could pluck from the ether some pros and cons for every blade type if you like:

square (ie its sides touch the side of the groove that it cuts) - cheaper to manufacture, but produce more resistance in the cut (whether you notice it or not ).

relieved (ie, there is a chamfer on the rear edges of the blade, but the front touches the side of the groove) - like the Stanley and Record blades for their plough/plow planes. - less resistance in the cut, more expensive to manufacture.

trapezoidal (ie there is a bevel all the way up the blade and on the whole of the side, but the front edges touch the groove sides) - imagine a bevel edged chisel. - less resistance, more expensive to manufacture. Actually I'm not quite sure what's the advantage over the relieved type? The additional removal of material from the cutter would perhaps weaken it to the detriment of the cut? Perhaps I'm mis-reading the description.

flared (the section of the blade is rectangular, but the front and rear faces are reduced slightly from the edges) - least possible resistance and some argument it gives the plane wiggle room (for want of a better term) but most expensive to manufacture and more awkward to maintain day to day.

When it comes to the flared I've not tried one to say whether it's "better" or not, but assuming it is, is it improvement enough to outweigh the disadvantages? Or as I think Mike's point is - are those improvements even necessary? Jake obviously passionately believes yes. I'm sceptical. In the same way it seems LV think the disadvantages of cost outweigh the advantages of relieved cutters. I don't, while Derek doesn't find it an issue. Now none of us are actually wrong, but our priorities of cost, effort, speed and so forth are evidently different. So what's to argue about? Personal preference. You might as well go into John Cleese's office and pay for an argument for all the good it'll do. ;D

Cheers, Alf

[ThePlowIdiot]

I think Alf has pretty much summed up the issue.

As I said on the UBeaut forum, it is mainly an academic exercise. Because the day to day reality--whether one desires to acknowledge it or not--is that billions of feet of grooving has been done with cutters of whatever configuration.

While I have not run a billion feet of grooves using a plow that has these failures of blade shapes so contested by a single person, I have run more than a few in 30 or more years.

It isn't that Jake is wrong, as Alf says. It is all about (to me) the "why bother"? A groove is 1/4" to 3/8" deep in most all circumstances. Making that "easier" is simply unnecessary. Oops. Should I use the trite acronym IMHO?

In my little experience with grooving and the blades used, and in particular with vintage blades, a bigger issue is a bit of dubbing along the leading sides of the blades. I don't have the Veritas plow, but looking at the pictures of the blades I do not see a rounded (dubbed) leading edge where the sides meet the face of the blades. That does cause binding because of that slight radius.

Jakes concept is akin to set on a saw. Not a bad thing. However, nearly any saw can cut 1/4" with zero set without issue. All it takes is that the leading edge of the saw's teeth be not dubbed. I can pretty much gaurantee one will not experience an issue even with a fairly coarse saw in that circumstance if the cut is shallow.

People get passionate about inanimate objects. I get that. People should not come to written blows over their passion.

I don't know what the point of this thread is. I would hope that it isn't just to stir the pot.

Take care, Mike

[paulchapman]

Well said, Alf and Mike

As with all things to do with the performance of tools, it depends how far you want to take it towards perfection.

Pity it all gets so heated but, in another sense, it's good that people have a bit of passion, even if it is only about a plane

Cheers

Paul

[pam]

Sounds like a lot of work and many blades in possession to test Jake's hypothesis (my assumption that he knows "the answer" and is looking for confirmation, but I'm willing to be corrected). It would be so much easier to test blade behavior with chisels (firmers, bevel edged used cutting edge up or down, shogi chisels used cutting edge up and down, and tapered versions of all three about covers the options, adds a few).

Pam

[Scrit]

jmk89 said:

Has anyone done any experiments on whether square or relieved cutters are better? Has anyone used trapezoidal or flared cutters? Does anyone care?

I think that many woodworkers who use TCT circular saw blades may have the answer right in front of them, but be unaware that they have. Machine tooling need to have relief angles on the sides to ensure clean cutting and reduce binding, hence the trapezoidal shape of the average TCT saw tooth. Similarly those carbide tips are wider than the body they are mounted on, partly to permit multiple grinds and partly to effect binding/friction-free running. I see no reason why the same principles applied to a cutter with potentially long contact edges, such as a rebate or plough plane blade, would not result in advantages in ease of use and reduced cutting force being required

Scrit

[jmk89]

Thanks for all who have bothered to reply. I wasn't trying to stir the pot, but just to see if someone has actually done the work - the one advantage that Jake has in his arguments is that he has flared the blades and used them extensively. My fear is that when people raise the temperature of these discussions in the way that happened here, others with valid points of view or experience to contribute are discouraged from adding their two pennorth lest they be flamed. So I wanted to ask the opinions on the issue from a group who might have relevant knowledge.

Alf - your analysis is about where I came to, although Jake says the flaring isn't so hard. That is why sometime I must do the experiment and see what I reckon.

Mike - I am interested in your point of dubbed corners - the point has been lost in the WWF discussion and I am not quite sure that I follow it.

Scrit - I reckon you are right - the circular saw teeth are a good analogy. Having a look at mine, they are both trapezoidal in cross- section and flared along the length of the tooth (ie the kerf of the tooth on the circumference is wider than the kerf closer to the bottom of the gullets), so these are really applying both Mike and Jake's points

[derekcohen]

Hi Jeremy

I think that Alf and Mike have summed up the points I made in that "discussion". My conclusion to Jake, in regard to his "flared" blades, was that it was not whether it worked (since I was in no doubt that it did), but whether it was absolutely necessary (as he believes) - since other options worked as well. All options have different trade offs.

Regards from Perth

Derek

[dom]

Welcome Derek, very nice to have you here.

[paulchapman]

Hi Derek - you found us then. Welcome.

Cheers

Paul

[noel]

Interesting discussion down below. Learnt a bit about blades too. From somebody who knows zilch about plough planes I'd be interested in trying one someday. That's the beauty about this business, every day is a school day.

See Devon Woody has been made a mod on Ubeaut...........

[jaco]

Hello Derek!

Baie welkom hier by ons, bly jy het jou pad gevind!
;D ;D ;D

[derekcohen]

Nou ja, hoe gaan dit Jaco? Is die Windhoek koud?

Beste van Perth af

Derek

[jaco]

Man ja, die Windhoek is lekker koud vir die tyd van die jaar.

Dit moet baie goed gaan daar met julle in Perth oor die kersgety, en alles van die beste vir 2008!

Groete
Phil